With the newest beta driver, the frontend of MythTV crashes upon start. It resolves certain OpenGL symbols dynamically and thus ends up using libGLESv2. This causes a crash when it calls glGenBuffers().
Reducing it to a simple test case with just a call to glGenBuffers(1, &some_temp) from libGLESv2 reproduces the crash reliably here.
The crash does naturally not happen if Mesa is used-- neither with the test case, nor with MythTV.
Here is the connected bug report over at Gentoo’s bugzilla with some more infos:
I hope that helps. If there is any more info needed, please let me know.